JP6184334B2 - Particle beam irradiation apparatus and control method thereof - Google Patents

Description

  Embodiments of the present invention relate to a particle beam irradiation apparatus for performing cancer treatment by irradiating an affected area to be irradiated with a heavy particle beam such as carbon, a proton beam, or the like, and a control method thereof.

  As an irradiation method of the particle beam therapy technique, there is a scanning irradiation method in which irradiation is performed by virtually cutting an affected part of a patient in a three-dimensional lattice shape. In this scanning irradiation method, the beam axis direction can be used without using a shape collimator for limiting the irradiation area or a bolus for adjusting the depth and direction of the beam irradiation (sometimes called a range compensator). Can be adjusted to the affected area with high accuracy. According to this scanning irradiation method, exposure to normal cells can be suppressed as compared with the conventional two-dimensional irradiation method.

  The scanning irradiation method is roughly classified into a spot scanning irradiation method that stops beam emission when the irradiation point is changed, and a raster scanning irradiation method that does not stop beam emission when the irradiation point is changed.

  In the scanning irradiation method, a position monitor is provided at the irradiation port to ensure that the beam is irradiated at the correct position.

  As an example of the position monitor for scanning irradiation, for example, the electrode portion of the collection electrode of the ionization chamber is divided into a large number of strips that are electrically unconnected in one axial direction. It is connected. An integration unit is provided inside the measurement circuit, and an amount of electricity corresponding to the charge collected in each strip is stored for each irradiation spot. The voltage output from the integrator is taken out as a digital signal by an A / D converter (hereinafter referred to as “ADC circuit”). Then, the spot position is calculated by executing an operation such as centroid calculation on these digital signals.

  In addition, for organs that move each time they breathe, such as the lungs and liver, breathing synchronized irradiation method that irradiates in synchronism with the timing of exhalation where the movement of the organ becomes the smallest in the breathing movement, and the amount of movement of the affected part In accordance with the above, there is a moving body tracking irradiation method in which the irradiation position is changed.

  Furthermore, the particle beam irradiation apparatus described in Patent Document 1 measures and displays a two-dimensional dose distribution during scanning.

JP 2011-161056 A

  By the way, in the above-mentioned respiratory synchronous irradiation method, the beam is irradiated only at the timing of expiration when the movement of the organ becomes the smallest in the respiration operation, so that one irradiation is performed as compared with the organ that does not move by respiration. The time will be longer. As a result, there are problems in that the restraint time on the patient is increased, the burden on the patient is increased, and the number of treatments per day is reduced.

  In addition, in the case of the moving body tracking irradiation method, tracking in the lateral direction perpendicular to the beam axis can be tracked relatively easily, but tracking in the beam axis direction dynamically changes the beam energy irradiated to the patient. Therefore, there was a problem that it was difficult to operate the accelerator.

  Therefore, the embodiment of the present invention has been made to solve the above-described problem, and it is possible to irradiate a beam with high accuracy in a shorter time even to an affected part that moves three-dimensionally by breathing or the like. An object of the present invention is to provide a particle beam irradiation apparatus and a control method therefor.

In order to achieve the above object, a particle beam irradiation apparatus according to the present embodiment includes a beam generation unit that generates a particle beam, a beam emission control unit that controls emission of the particle beam, and the particle beam. A beam scanning unit that performs two-dimensional scanning, a dose monitor unit that integrates a signal corresponding to the irradiation dose irradiated to the irradiation target, and a plurality of first linear electrodes arranged in parallel in the first direction, A position monitoring unit in which two linear electrodes are arranged in parallel in a second direction orthogonal to the first direction, a first signal output from each first linear electrode, and each second A center-of-gravity position calculation unit that calculates the center-of-gravity position of the particle beam from a second signal output from the linear electrode, a respiration waveform detection unit that detects a respiration state of the irradiation target as a respiration waveform, and the respiration Displacement amount of the affected area of the irradiation target according to the waveform Respiratory synchronization correction processing unit that sets information to be corrected and calculates the actual irradiation position from the displacement amount of the affected area, and controls to irradiate a plurality of irradiation spots collectively for each group based on the displacement amount of the affected area A control unit that divides a region to be irradiated with the particle beam into a plurality of spot groups, and irradiates the particle beam with an arbitrary number of irradiation spots as one spot group. The spot group is set, and during the irradiation of the particle beam, it is determined which of the irradiation spots in the spot group is irradiated with the particle beam based on the actual irradiation position. The irradiation dose is counted, and when one of the irradiation spots reaches the planned dose, the irradiation of the particle beam to the spot group is finished. Then, it is set to irradiate the particle beam to the next spot group, and after irradiating all the spot groups, select the irradiation spot that has not reached the planned dose, and in the respiratory waveform Control to irradiate the particle beam when the waveform is exhaled, and when the selected irradiation spot reaches a predetermined dose, select the irradiation spot that does not reach another planned dose The irradiation spot is controlled to reach a predetermined dose .
In addition, the particle beam irradiation apparatus according to the present embodiment includes a beam generation unit that generates a particle beam, a beam emission control unit that controls emission of the particle beam, and a beam that performs two-dimensional scanning of the particle beam. A scanning unit, a dose monitor unit that integrates signals according to the irradiation dose irradiated to the irradiation target, a plurality of first linear electrodes are arranged in parallel in the first direction, and a plurality of second linear electrodes are arranged A position monitor unit arranged in parallel in a second direction orthogonal to the first direction, a first signal output from each first linear electrode, and an output from each second linear electrode A centroid position calculation unit that calculates a centroid position of the particle beam from the second signal that is generated, a respiration waveform detection unit that detects a respiration state of the irradiation target as a respiration waveform, and the irradiation according to the respiration waveform Information to correct the displacement of the affected area is set And a respiratory synchronization correction processing unit that calculates an actual irradiation position from the displacement amount of the affected part, and a control unit that controls to irradiate a plurality of irradiation spots collectively for each group based on the displacement amount of the affected part, The control unit divides an area to be irradiated with the particle beam into a plurality of spot groups with an arbitrary number of irradiation spots as one spot group, and determines the arbitrary spot group to be irradiated with the particle beam. And determining, during the irradiation of the particle beam, to which irradiation spot in the spot group the particle beam is irradiated based on the actual irradiation position, and counting the irradiation dose of each irradiation spot. When one of the irradiation spots reaches a predetermined dose, the irradiation of the particle beam to the spot group is finished and the next spot is stopped. When the group is set to irradiate the particle beam and the irradiation of all the spot groups in the region is completed, the number of irradiation spots smaller than the previous setting is set as one spot group, and the spot group is set in the region. A spot group that is reset and does not include an irradiation spot that has reached a predetermined dose among the reset spot groups is set as a spot group that irradiates the particle beam.

The particle beam irradiation apparatus control method according to the present embodiment includes a step in which a beam generation unit generates a particle beam, a step in which a beam emission control unit controls emission of the particle beam, and a beam scanning unit in the step A step of two-dimensionally scanning the particle beam, a step of integrating signals corresponding to the irradiation dose irradiated to the irradiation target by the dose monitor unit, and a center-of-gravity position calculating unit , wherein the plurality of first linear electrodes are the first A first signal that is arranged in parallel in a direction, a plurality of second linear electrodes are arranged in parallel in a second direction orthogonal to the first direction, and is output from each first linear electrode; Calculating a gravity center position of the particle beam from the second signal output from each of the second linear electrodes, and detecting a respiratory state of the irradiation target as a respiratory waveform by a respiratory waveform detection unit ; , breathing synchronization correction processing unit corresponding to the respiratory waveform Serial information for correcting the displacement amount of the affected part of the irradiation target is set, and the basis of the step of calculating an actual irradiation position from the displacement amount of the affected part, the first control unit is a plurality of irradiation spots on the displacement amount of the affected area possess a first control step of controlling so as to collectively irradiate each group, the Te, the first control step, the irradiation spot of any number as a spot group is irradiated with the particle beam An area is divided into a plurality of spot groups, an arbitrary spot group for irradiating the particle beam is set, and any of the spot groups in the spot group is set based on the actual irradiation position during the irradiation of the particle beam. It is determined whether the particle beam is irradiated to the irradiation spot, the irradiation dose of each irradiation spot is counted, and when one of the irradiation spots reaches the planned dose, the spot When the irradiation of the particle beam to the next group is completed and the particle beam is irradiated to the next spot group, and the irradiation to all the spot groups is completed, the planned dose has not been reached. The irradiation spot is selected and controlled to irradiate the particle beam when the breathing waveform is in the respiration waveform. When the selected irradiation spot reaches a predetermined dose, another planned dose is reached. It is characterized in that all the irradiation spots are controlled to reach a predetermined dose by selecting no irradiation spots .
Further, the control method of the particle beam irradiation apparatus according to the present embodiment includes a step in which the beam generation unit generates the particle beam, a step in which the beam emission control unit controls the emission of the particle beam, and a beam scanning unit. Includes a step of two-dimensionally scanning the particle beam, a step of integrating signals according to an irradiation dose irradiated to the irradiation target by the dose monitor unit, and a centroid position calculating unit including a plurality of first linear electrodes. A first signal that is arranged in parallel in one direction, a plurality of second linear electrodes are arranged in parallel in a second direction orthogonal to the first direction, and is output from each first linear electrode And a step of calculating a gravity center position of the particle beam from the second signals output from the second linear electrodes, and a respiratory waveform detector detects the respiratory state of the irradiation target as a respiratory waveform Process and respiratory synchronization correction processing unit Information for correcting the displacement amount of the affected area to be irradiated is set, and the actual irradiation position is calculated from the displacement amount of the affected area, and the first control unit defines a plurality of irradiation spots as the displacement amount of the affected area. And a first control step for controlling the irradiation so as to be collectively performed for each group based on the first control step, wherein the first control step uses an arbitrary number of irradiation spots as one spot group, and An area to be irradiated is divided into a plurality of spot groups, an arbitrary spot group for irradiating the particle beam is set, and any of the spot groups can be determined based on the actual irradiation position during the irradiation of the particle beam. It is determined whether or not a particle beam is irradiated to the irradiation spot, and the irradiation dose of each of the irradiation spots is counted, and if one of the irradiation spots reaches the planned dose, End the irradiation of the particle beam to the spot group and set the irradiation of the particle beam to the next spot group. When the irradiation of all the spot groups in the region is completed, Re-set a spot group in the area with a smaller number of irradiation spots than the set as a spot group, and irradiate the particle group with a spot group that does not include the irradiation spot that has reached the planned dose among the reset spot groups It is set as a spot group to be performed.

  According to the present embodiment, it is possible to irradiate the affected part that moves three-dimensionally by breathing or the like with high accuracy in a shorter time.

It is a block diagram which shows the structure of the particle beam irradiation apparatus of 1st Embodiment. It is a time chart which produces | generates the gate signal in a respiration waveform detection apparatus. It is explanatory drawing which shows the structure of a strip type position monitor part. It is a flowchart which shows the basic process in the case of performing respiratory synchronous irradiation by the raster scanning irradiation method among three-dimensional scanning irradiation. It is a timing chart which shows an example of management and control of a dose and a particle beam position. It is a block diagram which shows the detailed structure of the gravity center position calculation part in FIG. It is explanatory drawing which shows the example at the time of making a spot group into two dimensions. It is a flowchart which shows the process example of the three-dimensional scanning irradiation in 1st Embodiment. It is explanatory drawing which shows the irradiation condition of a spot group. It is the figure which showed the change of the gate signal at the time of changing a threshold value in the respiration waveform detection apparatus of the particle beam irradiation apparatus of 2nd Embodiment. It is explanatory drawing which shows the spot group reset for a hybrid control process. It is explanatory drawing which shows the spot group reset for a hybrid control process. It is a flowchart which shows the hybrid control process in 2nd Embodiment.

  Embodiments of a particle beam irradiation apparatus and a control method thereof will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the particle beam irradiation apparatus of the first embodiment. As shown in FIG. 1, the particle beam irradiation apparatus 1 includes a beam generation unit 10, an emission control unit 20, a beam scanning unit 30, an X electromagnet 30a, a Y electromagnet 30b, a dose monitor unit 50, a position monitor unit 51, A ridge filter 60, a range shifter 70, a control unit 80, a gravity center position calculation unit 90, a respiratory waveform detection device 250, and the like are provided.

  The particle beam irradiation apparatus 1 irradiates a particle beam obtained by accelerating particles such as carbon and protons at high speed toward an affected area 200 of a cancer patient 100 as an irradiation target, and performs cancer treatment. It is. In the particle beam irradiation apparatus 1, the affected part 200 can be discretized into three-dimensional lattice points, and a three-dimensional scanning irradiation method of sequentially scanning a particle beam with a small diameter at each lattice point can be performed. Specifically, the affected area 200 is divided into flat units called slices in the axial direction of the particle beam (Z-axis direction in the coordinate system shown in the upper right of FIG. 1), and divided slices Zi, slices Zi + 1, slices Zi + 2, etc. The three-dimensional scanning is performed by sequentially scanning the two-dimensional lattice points of each slice (the lattice points in the X-axis and Y-axis directions in the coordinate system shown in FIG. 1).

  The beam generator 10 generates particles such as carbon ions and protons, and generates a particle beam by accelerating these particles to an energy that can reach deep into the affected area 200 by an accelerator (main accelerator) such as a synchrotron. ing.

  The emission control unit 20 performs on / off control of the emission of the particle beam generated by the beam generation unit 10 based on the control signal output from the control unit 80, that is, the interlock signal and the beam emission permission signal. Yes.

  The beam scanning unit 30 deflects the particle beam in the X direction and the Y direction and scans the slice surface in two dimensions. The X electromagnet 30a that scans in the X direction and the Y electromagnet that scans in the Y direction. The exciting current 30b is controlled.

  The range shifter 70 controls the irradiation position of the affected part 200 in the Z-axis direction. The range shifter 70 is composed of, for example, an acrylic plate having a plurality of thicknesses, and by combining these acrylic plates, the energy of the particle beam passing through the range shifter 70, that is, the range of the body is determined in the Z-axis direction of the slice in the affected part 200 It can be changed step by step according to the position of. The size of the in-vivo range by the range shifter 70 is normally controlled so as to change at regular intervals, and this interval corresponds to the interval between lattice points in the Z-axis direction. As a method of switching the range of the body, in addition to a method of inserting an attenuation object on the path of the particle beam as in the range shifter 70, the energy of the particle beam is changed by controlling the beam generator 10. It may be a method.

  The ridge filter 60 is provided for diffusing a sharp peak of the dose in the body depth direction called a Bragg peak. Here, the diffusion width of the Bragg peak by the ridge filter 60 is set to be substantially equal to the thickness of the slice, that is, the interval between the lattice points in the Z-axis direction.

  The dose monitor unit 50 is for monitoring the dose irradiated to the affected part 200 of the cancer patient 100 to be irradiated, and collects the charges generated by the ionizing action of the particle beam in the casing by the parallel electrodes. It is configured by an ionization chamber, a SEM (Secondary Electron Monitor) device that measures secondary electrons emitted from a secondary electron emission film disposed in the casing, and the like.

  The position monitor unit 51 is for identifying whether or not the particle beam scanned by the beam scanning unit 30 is in the correct position. Similar to the dose monitor unit 50, it has parallel electrodes for charge collection. As for the charge collection electrode of the position monitor 51, linear electrodes (for example, a plurality of strip electrodes or electrodes made of a plurality of wires) are arranged in parallel in the X direction and the Y direction, respectively. An arrangement in which a plurality of strip electrodes are arranged is called a strip type, and an arrangement in which a plurality of wire electrodes are arranged is called a multi-wire type.

  The respiratory waveform detection device 250 measures the amount of displacement of the body surface due to respiration, etc., creates a gate signal for permitting irradiation at the timing of expiration when the displacement of the affected part 200 is small, and outputs it to the control unit 80 (FIG. 2). . The control unit 80 uses this gate signal as a condition for creating a beam extraction permission signal to be output to the extraction control unit 20.

  FIG. 3 is an explanatory diagram showing the configuration of the strip-type position monitor unit 51. As shown in FIG. 3, the position monitor 51 includes an X electrode 51 a in which a plurality of strip electrodes (a plurality of first linear electrodes) are arranged in parallel in the X-axis direction (first direction), and a plurality of electrodes Strip-shaped electrodes (a plurality of second linear electrodes) have Y electrodes 51b arranged in parallel in the Y-axis direction (second direction orthogonal to the first direction).

  The control unit 80 is for controlling the particle beam irradiation apparatus 1 as a whole, measures the irradiation dose for each lattice point, checks the soundness of the irradiation position for each spot, turns on beam emission to the emission control unit 20, Off control, instructions regarding beam scanning to the beam scanning unit 30, range shifter thickness control accompanying the slice change to the range shifter 70, and the like are performed.

  FIG. 4 is a flowchart showing a basic process in the case of performing respiratory synchronization irradiation by the raster scanning irradiation method in the three-dimensional scanning irradiation. The only difference from the spot scanning irradiation method is whether or not the particle beam irradiation is temporarily stopped or not stopped at the spot switching timing, and the large flow is hardly changed.

  As shown in FIG. 4, first, the affected part 200 is virtually divided into a plurality of slices with respect to the particle beam axis, and one of the divided slices is selected. First, for example, the slice Zi at the deepest position of the affected part 200 is selected. Further, the combination of the incident (introduction) energy of the particle beam and the acrylic plate in the range shifter 70 is selected and set according to the position of the selected slice (step ST1).

  Next, the number M of lattice points to be irradiated with the particle beam and the position (Xi, Yi) [i = 1 to M] of the lattice points, that is, the spot to be irradiated, are selected according to the shape of the affected part in the selected slice, and the beam The scanning unit 30 sets the scanning position of the particle beam at the lattice point position (Xi, Yi) on the slice (step ST2).

  It is determined whether or not the gate signal from the respiratory waveform detector 250 is ON (the respiratory waveform is exhaled) (step ST3), and the particle beam is emitted only when the gate signal is ON (step ST3: Yes). It is started (step ST4). When the gate signal is other than ON (step ST3: No), the emission of the particle beam is stopped (step ST5).

  The energy distribution of the particle beam that has passed through the X electromagnet 30a and the Y electromagnet 30b set by the beam scanning unit 30 is expanded in the Z-axis direction by the ridge filter 60 so that the body range distribution width corresponds to the slice width. Has been.

  The irradiation dose for the grid point (Xi, Yi) is monitored by a signal (current, voltage, frequency pulse, etc.) proportional to the dose output from the dose monitor unit 50, and the irradiation dose for the target grid point reaches the planned dose. Then, a dose expiration signal flag is set (step ST6).

  The position of the particle beam is stopped until the planned dose at each grid point is reached, and moves to the next grid point after reaching the planned dose.

  When the planned dose is reached, the dose and the center of gravity (irradiation) position of the irradiated particle beam are recorded in the storage memory (step ST7), and the particle beam position is moved to the next spot. This process is repeated up to the final spot of the target slice (step ST8).

  When irradiation to one slice is completed (step ST8: No), the beam emission is temporarily stopped (step ST9), the process returns to step ST1 again to select the next slice, and the incident energy of the particle beam and the range shifter 70 Change the combination setting of acrylic plates. The above processing is repeated until the final spot is reached (step ST10).

  Each item necessary for the above irradiation procedure is described in a data file called an irradiation pattern file, for example, and transferred to the control unit 80 before the start of treatment irradiation. The irradiation pattern file includes a range shifter thickness for giving a slice position for each lattice point, a driving current value for the X electromagnet 30a and the Y electromagnet 30b for giving a particle beam position corresponding to the lattice point (X, Y), and each lattice. The irradiation dose, irradiation position, allowable error from the irradiation position, etc. for the point are described in the irradiation order.

  FIG. 5 is a timing chart showing an example of management and control of dose and particle beam position.

  The excitation currents of the two electromagnets shown in FIGS. 5A and 5B correspond to the position setting values in the biaxial directions (X, Y). FIG. 5C shows a beam emission state. When the dose (dose monitor integrated dose, FIG. 5D) measured by the dose monitor unit 50 reaches a set value, a dose expiration signal (FIG. 5E) is output. When the exciting current of the electromagnet is changed and reaches a set value, the exciting current value is held. The beam irradiation point moves according to the change in the excitation current of the electromagnet.

  As shown in FIGS. 5F and 5G, in the position monitor unit 51, a spot switching command is output from the control unit 80 to the centroid position calculation unit 90 as a control signal based on the signal generated by the dose expiration signal, and the centroid Based on the current value detected from each channel of the position monitor unit 51, the position calculation unit 90 outputs the latest (final) centroid calculation result at that time from the centroid position calculation unit 90 to the control unit 80.

  The center-of-gravity position calculation unit 90 performs center-of-gravity calculation processing at a constant period (for example, a period of 5 μs) even if a spot switching command is not input from the control unit 80 in order to measure an irradiation dose distribution in units of slices, for example. .

  FIG. 6 is a block diagram illustrating a detailed configuration of the gravity center position calculation unit 90. The number (number of channels) of the X electrodes 51a and Y electrodes 51b of the position monitor unit 51 is not particularly limited. However, in the following description, the number of channels in both the X direction and the Y direction is 120 channels as an example. To do.

  As shown in FIG. 6, the output current of the X electrode 51a is converted into a voltage by a current-voltage conversion (I / V conversion) unit 911a, amplified to an appropriate voltage by an amplification unit 912a, and then converted into an AD converter (ADC). ) 92a is converted into a digital signal. The next-stage data correction processing unit 93a performs offset correction processing and averaging processing on the digital signal and outputs the result to the position calculation unit 94a.

  The I / V conversion unit 911a, the amplification unit 912a, the ADC 92a, and the data correction processing unit 93a are provided for each of the X electrodes 51a. In this example, the number of channels is 120.

  Similarly, an I / V conversion unit 911b, an amplification unit 912b, an ADC 92b, a data correction processing unit 93b, and a position calculation unit 94b for 120 channels are provided for each of the Y electrodes 51b.

  In the next-stage position calculation units 94a and 94b, from the amplitude values of the channel signals in the X and Y directions subjected to the offset correction process and the averaging process, the gravity center position in the X direction of the particle beam and the Y direction Each center of gravity is calculated.

  The one-dimensional beam shape (X) extraction unit 95a calculates the one-dimensional beam shape in the X direction (first direction) from the amplitude values of the plurality of X channel signals (first signals) around the calculated X direction center of gravity position. (First beam shape) is obtained. The one-dimensional beam shape (Y) extraction unit 95b similarly obtains the one-dimensional beam shape in the Y direction.

  The two-dimensional beam shape extraction unit 96 calculates the two-dimensional beam shape G (Xi, Yj) from the product of the respective one-dimensional beam shapes F (Xi) and F (Yj) in the X direction and the Y direction obtained as described above. )

  The calculated two-dimensional beam shape G (Xi, Yj) is transferred to the storage unit 97.

  A signal indicating the dose profile (two-dimensional distribution of dose) accumulated and stored in the storage unit 97 is sent to the display unit 98 in units of slices, for example, and displayed on the screen of the display unit 98 corresponding to the storage area of the storage unit 97 in units of slices. The dose profile is easily visible.

  The particle beam irradiation apparatus 1 according to the present embodiment provides means capable of irradiating an organ moving by respiration and the like in a shorter time and with higher accuracy than in the past.

  Next, the particle beam irradiation apparatus according to the first embodiment will be described again with reference to FIG.

  As shown in FIG. 1, the control unit 80 is provided with a breathing synchronization correction processing unit 83. The respiratory waveform detection device 250 as a respiratory waveform detection unit has waveform information as a signal input to the control unit 80 in addition to the gate signal.

  In the respiratory synchronization correction processing unit 83, information for correcting the displacement amount of the affected part 200 according to the respiratory waveform is set. This information is calculated in advance by image information obtained by X-ray imaging (or CT (Computed Tomography imaging: computed tomography imaging)) synchronized with breathing at the time of treatment planning.

  The respiratory waveform detection device 250 is based on an image (moving image) from an X-ray imaging device taken from an oblique direction during treatment irradiation, in addition to a device for measuring the amount of movement of the body surface (external respiratory waveform detection device). Alternatively, a device (an internal respiratory synchronization device) that directly measures the amount of movement of the affected area or surrounding tissue (such as bone or metal marker) may be used. In this case, the signal input to the control unit 80 can be not the waveform information but the actual movement amount of the affected part itself.

  Normally, irradiation control is performed for each irradiation spot (lattice point). However, in this embodiment, irradiation control is performed by collecting a plurality of spots into a certain group (spot group). The spot group is determined based on the amount of movement of the affected part due to breathing or the like.

  FIG. 7 is an explanatory diagram showing an example in which the spot group is two-dimensional.

  As shown in FIG. 7, the numbers in each column indicate the planned dose for each grid point (spot). This scheduled dose is recorded in the setting area unit 81 of the control unit 80. When the movement amount of the affected part 200 by respiratory synchronization is within 3 spots, 3 × 3 spots surrounded by a thick frame are collectively controlled as a spot group.

  In the example shown in FIG. 7, for convenience, a 3 × 3 spot surrounded by a thick line is defined as a two-dimensional spot group. However, the movement amount of the affected area 200 is three-dimensional or biased. In such a case, it is possible to set a three-dimensional spot group or a spot group having a shape other than a square according to the movement amount.

  FIG. 8 is a flowchart showing a processing example of three-dimensional scanning irradiation in the first embodiment. This three-dimensional scanning irradiation can be roughly divided into a group scan control processing unit and a gating control processing unit. This flowchart is also a flow assuming the raster scanning irradiation method, but the large flow is hardly changed even in the spot scanning method.

  In the group scan control processing unit, first, the combination of the incident energy of the particle beam and the acrylic plate in the range shifter 70 is selected and set according to the position of the selected slice (step ST11).

  Next, the spot group of the corresponding slice is selected, the beam scanning unit 30 sets the scanning position of the particle beam at the lattice point position on the slice (step ST12), and the beam is introduced (step ST13).

  After a certain period of time has elapsed (step ST14), 1) the irradiation dose so far is measured, 2) the displacement of the affected area is calculated from the respiratory waveform from the respiratory waveform detector 250, and 3) the gravity center position calculating unit 90 The actual irradiation position is calculated based on the irradiation position information calculated in step 2 and the displacement of the affected part in 2), and 4) the irradiation dose in 1) is added to the recording area 82 of the corresponding spot (step ST15). A specific example of processing in steps ST14 to ST15 is shown in FIG.

  That is, as shown in FIG. 9, a planned dose is set for each spot of the spot group. Since the particle beam is not irradiated at first, each spot has 0 count. When a certain time has elapsed, the dose at that time is set to 450 counts. Here, if the irradiation position information calculated by the gravity center position calculation unit 90 is (0, 0), the value of the respiratory synchronization correction processing unit 83 is also (0, 0), and the center position is counted 450 times.

  If the (0, 1) deviation information is output from the respiratory synchronization correction processing unit 83 at the next timing and the irradiation dose for a certain time is 460 counts, the spot of the deviation portion is counted 460 times. If (-1, 1) information that is shifted is output and the irradiation dose for a certain period of time is 430 counts, the spot of the shifted portion is counted 430 times.

  Further, when (1, 1) information that is shifted from the respiratory synchronization correction processing unit 83 is output and the irradiation dose for a certain time is 500 counts, the spot of the shifted portion is counted 500 times. Next, if the irradiation position information calculated by the barycentric position calculation unit 90 is (0, 0), the value of the respiratory synchronization correction processing unit 83 is also (0, 0), and the center position is counted by 420. Therefore, since the dose of this spot has reached 1980 counts and has reached the planned dose, switching to the next spot group is performed.

  Steps ST14 and ST15 are repeated until a spot that has reached the planned dose (expired spot) appears in the spot group as described above (step ST16). If a spot that has reached the planned dose appears, setting to the next spot group is performed. (Step ST17).

  When the irradiation to the spot group for one slice is completed (step ST17: Yes), the beam emission is temporarily stopped (step ST18), the next slice is selected by returning to step ST11, and the incident energy of the particle beam is determined. The setting of the combination of acrylic plates in the range shifter 70 is changed. The above processing is repeated until the final spot group is reached (step ST19), and then the process proceeds to the gating control processing unit.

  In the gating control processing unit, first, the combination of the incident energy of the particle beam and the acrylic plate in the range shifter 70 is selected and set according to the position of the selected slice (step ST20).

  Next, in the selected slice, a spot that has not been irradiated to the planned dose is selected, and the beam scanning unit 30 sets the scanning position of the particle beam to the lattice point position (Xi, Yi) on the slice (step ST21). .

  It is determined whether the gate signal from the respiratory waveform detection device 250 is ON (the respiratory waveform is exhaled) (step ST22), and the particle beam is emitted only when the gate signal is ON (step ST22: Yes). It starts (step ST23). When the gate signal is other than ON (step ST22: No), the emission of the particle beam is stopped (step ST24).

  The energy distribution of the particle beam that has passed through the X electromagnet 30a and the Y electromagnet 30b set by the beam scanning unit 30 is expanded in the Z-axis direction by the ridge filter 60 so that the body range distribution width corresponds to the slice width. Has been.

  The irradiation dose for the grid point (Xi, Yi) is monitored by a signal (current, voltage, frequency pulse, etc.) proportional to the dose output from the dose monitor unit 50, and the irradiation dose for the target grid point reaches the planned dose. Then, a dose expiration signal flag is set (step ST25).

  The position of the particle beam stops until reaching the planned dose at each grid point until the planned dose is reached at each grid point, and moves to the next grid point after reaching the planned dose.

  When the planned dose is reached, the dose of the irradiated beam and the position of the center of gravity are recorded in the recording area 82 (step ST26), and the particle beam position is moved to the next spot. This process is repeated up to the final spot of the target slice (step ST27).

  When irradiation to one slice is completed (step ST27: No), beam emission is temporarily stopped (step ST28), the process returns to step ST21, the next slice is selected, and the setting of the range shifter 70 is changed. The above processing is repeated until the final spot is reached (step ST29).

  As described above, according to the present embodiment, during group scan control, even if the affected area moves three-dimensionally due to breathing or the like, the irradiation of the particle beam is continued with high accuracy without stopping the introduction of the particle beam. It becomes possible. As a result, the particle beam can be irradiated with high accuracy and the irradiation time of the particle beam can be shortened.

  Further, according to the present embodiment, since the gating control process is executed after the group scan control process, the particle beam is irradiated to the spot that has not been irradiated to the planned dose in the group scan control process. On the other hand, irradiation can be performed with higher accuracy.

(Second Embodiment)
In the first embodiment, the gating control process is executed after the group scan control process. In the second embodiment, the group scan control process and the gating process are performed between the group scan control process and the gating control process. It is characterized in that a control process (hereinafter referred to as a hybrid control process) in which a mixing control process is mixed is included.

  The group scan control process does not use a gate signal based on the comparison between the respiration waveform and the threshold value, but irradiates all waveform regions. In the gating control process, the threshold value is set to be only during expiration. Irradiating.

  On the other hand, in the hybrid control process of this embodiment, as shown in FIG. 10, the threshold A is raised to some extent like the thresholds B and C, and is longer than the gate signal A during gating control shown in FIG. In such a setting, the gate signals B and C are set to be ON, and the group scan control is performed during the period. Since the movement amount of the affected area while the gate signal is ON is smaller than the movement amount of the affected area throughout the breathing, the spot group can be set relatively small.

  By resetting the spot group to a smaller size in this way, spot groups that have not expired will come out, so irradiation with group scan control is performed on the reset spot group while the gate signal is ON. Do. It is also possible to control by changing (lowering) the threshold value as the irradiation proceeds (see FIGS. 11 and 12).

  FIG. 11 and FIG. 12 are explanatory diagrams showing hybrid control processing spot group resetting. FIG. 11 shows a state in which the group scan control process has been completed with a spot group of 5 × 5 spots within the thick frame. FIG. 12 shows the spot group resetting with 3 × 3 spots in the bold frame, and the bold italic part is the target of the hybrid control process.

  FIG. 13 is a flowchart showing a hybrid control process in the second embodiment. This is also a flow assuming the raster scanning irradiation method, but the large flow is hardly changed even in the spot scanning method.

  In the hybrid control process, first, the threshold level and the spot group volume setting are changed. The threshold level may be a signal for internal processing of the control unit 80 (a gate signal is generated by the control unit 80), and a threshold change request is output from the control unit 80 to the respiratory waveform detection device 250. Alternatively, a gate signal may be created by the respiratory waveform detection device 250 (step ST31).

  Next, the combination of the incident energy of the particle beam and the acrylic plate in the range shifter 70 is selected and set according to the position of the selected slice (step ST32).

  Next, in the corresponding slice, a spot group having no expired spot is selected, and the beam scanning unit 30 sets the scanning position of the particle beam at the lattice point position on the slice (step ST33).

  It is determined whether or not the gate signal from the respiratory waveform detector 250 is ON (the respiratory waveform is exhaled) (step ST34), and the particle beam is emitted only when the gate signal is ON (step ST34: Yes). The process is started (step ST35). When the gate signal is other than ON (step ST34: No), the emission of the particle beam is stopped (step ST36).

  The energy distribution of the particle beam that has passed through the X electromagnet 30a and the Y electromagnet 30b set by the beam scanning unit 30 is expanded in the Z-axis direction by the ridge filter 60 so that the body range distribution width corresponds to the slice width. Has been.

  After a certain period of time (step ST37), 1) the irradiation dose so far is measured, 2) the amount of displacement of the affected area is calculated from the respiratory waveform from the respiratory waveform detector 250, and 3) the gravity center position calculating unit 90 The actual irradiation position is calculated based on the measurement result and the displacement amount of 2), and 4) the irradiation dose of 1) is added to the recording area of the corresponding spot (step ST38).

  Steps ST34 to ST38 are repeated until a spot that reaches the planned dose (expired spot) appears in the spot group (step ST39), and when a spot that reaches the planned dose appears, the setting is switched to the next spot group (step ST40). If No in step ST40, the process returns to step ST33.

  When the irradiation to the spot group for one slice is completed (step ST40: Yes), the beam emission is temporarily stopped (step ST41), the next slice is selected by returning to step ST32, and the incident energy of the particle beam is determined. The setting of the combination of acrylic plates in the range shifter 70 is changed. The above processing is repeated until the final spot group is reached (step ST42).

  When the irradiation with respect to one threshold level is completed (step ST43: Yes), the process returns to step ST31 to select the next (small) threshold level and change the volume setting of the spot group.

  The above processing is repeated until the final threshold level is reached, and then the process proceeds to gating control processing (step ST44).

  As described above, according to the present embodiment, during the hybrid control process, even if the affected part moves due to breathing or the like, the period during which the introduction of the particle beam is stopped can be shortened compared to the time of gating control, and the irradiation time can be reduced. This can be further shortened.

(Other embodiments)
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, in the first embodiment, the example in which the spot group is set to 3 × 3 and 5 × 5 spots in two dimensions has been described. However, the present invention is not limited to this, and the spot groups are set in other two dimensions. Alternatively, it may be set to three dimensions.

  DESCRIPTION OF SYMBOLS 1 ... Particle beam irradiation apparatus, 10 ... Beam generation part, 20 ... Ejection control part, 30 ... Beam scanning part, 30a ... Electromagnet for X, 30b ... Electromagnet for Y, 50 ... Dose monitor part, 51 ... Position monitor part, 51a ... X electrode of position monitor unit, 51b ... Y electrode of position monitor unit, 60 ... ridge filter, 70 ... range shifter, 80 ... control unit, 81 ... setting region unit, 82 ... recording region unit, 83 ... respiration synchronization correction processing , 90 ... gravity center position calculation unit, 911 a, 911 b ... current-voltage conversion (I / V conversion) unit, 912 a, 912 b ... amplification unit, 92 a, 92 b ... AD converter (ADC), 93 a, 93 b ... data correction processing unit 94a, 94b ... position calculation unit, 95a ... one-dimensional beam shape (X) extraction unit, 95b ... one-dimensional beam shape (Y) extraction unit, 96 ... two-dimensional beam shape extraction unit, 97 ... storage unit, 98 Display unit, 100 ... cancer patients (irradiation target), 200 ... affected area, 250 ... respiratory waveform detecting device (the respiratory waveform detecting unit)

Claims (10)

A beam generator for generating a particle beam;
A beam emission control unit for controlling the emission of the particle beam;
A beam scanning unit for two-dimensionally scanning the particle beam;
A dose monitor unit for integrating signals according to the irradiation dose irradiated to the irradiation target;
A plurality of first linear electrodes arranged in parallel in a first direction, and a plurality of second linear electrodes arranged in parallel in a second direction orthogonal to the first direction;
A center-of-gravity position calculation unit that calculates the center-of-gravity position of the particle beam from the first signal output from each first linear electrode and the second signal output from each second linear electrode When,
A respiratory waveform detector that detects a respiratory state of the irradiation target as a respiratory waveform;
Information for correcting the displacement amount of the affected part of the irradiation target according to the respiratory waveform is set, and a respiratory synchronization correction processing unit that calculates an actual irradiation position from the displacement amount of the affected part,
And a control unit for controlling to collectively irradiate each group based on a plurality of irradiation spots on the displacement amount of the diseased part,
The controller is
An arbitrary number of irradiation spots are set as one spot group, and the region irradiated with the particle beam is divided into a plurality of spot groups,
Set an arbitrary spot group to irradiate the particle beam,
During irradiation of the particle beam, determine which irradiation spot in the spot group is irradiated with the particle beam based on the actual irradiation position,
Count the irradiation dose of each irradiation spot,
When one of the irradiation spots reaches a scheduled dose, the irradiation of the particle beam to the spot group is terminated and set to irradiate the particle beam to the next spot group,
When the irradiation to all the spot groups is completed, select the irradiation spot that has not reached the planned dose, and control to irradiate the particle beam when the waveform is breathing in the respiratory waveform, Particle beam irradiation , wherein when the selected irradiation spot reaches a planned dose, all the irradiation spots are controlled to reach the planned dose by selecting the irradiation spot that has not reached another planned dose apparatus.   A beam generator for generating a particle beam;
  A beam emission control unit for controlling the emission of the particle beam;
  A beam scanning unit for two-dimensionally scanning the particle beam;
  A dose monitor unit for integrating signals according to the irradiation dose irradiated to the irradiation target;
  A plurality of first linear electrodes arranged in parallel in a first direction, and a plurality of second linear electrodes arranged in parallel in a second direction orthogonal to the first direction;
  A center-of-gravity position calculation unit that calculates the center-of-gravity position of the particle beam from the first signal output from each first linear electrode and the second signal output from each second linear electrode When,
  A respiratory waveform detector that detects a respiratory state of the irradiation target as a respiratory waveform;
  Information for correcting the displacement amount of the affected part of the irradiation target according to the respiratory waveform is set, and a respiratory synchronization correction processing unit that calculates an actual irradiation position from the displacement amount of the affected part,
  A control unit that controls to irradiate a plurality of irradiation spots collectively for each group based on the displacement amount of the affected part, and
  The controller is
  An arbitrary number of irradiation spots are set as one spot group, and the region irradiated with the particle beam is divided into a plurality of spot groups,
  Set an arbitrary spot group to irradiate the particle beam,
  During irradiation of the particle beam, determine which irradiation spot in the spot group is irradiated with the particle beam based on the actual irradiation position,
  Count the irradiation dose of each irradiation spot,
  When one of the irradiation spots reaches a scheduled dose, the irradiation of the particle beam to the spot group is terminated and set to irradiate the particle beam to the next spot group,
  When the irradiation of all the spot groups in the region is completed, the number of irradiation spots smaller than the setting so far is set as one spot group, and the spot group is reset in the region,
  A particle beam irradiation apparatus, wherein a spot group that does not include an irradiation spot that has reached a predetermined dose among the reset spot groups is set as a spot group that irradiates the particle beam. Information for correcting the amount of displacement of the affected area, the particle beam according to claim 1 or 2, characterized in Rukoto calculated by X-ray imaging or computer tomography image information synchronized with the breathing time of treatment planning Irradiation device. The respiration synchronization correction processing unit according to any one of claims 1 to 3, characterized in that calculating the actual irradiation position from the calculated irradiation position information at the displacement amount and the center-of-gravity position calculating unit of the affected area Particle beam irradiation equipment. The respiratory synchronization correction processing unit changes a threshold for creating a respiratory gate signal for irradiating the particle beam when the waveform is exhaled in the respiratory waveform according to an irradiation situation, and an affected part corresponding to the respiratory waveform 3. The particle beam irradiation apparatus according to claim 1, wherein the actual irradiation position is calculated from the amount of displacement . 3. The control unit according to claim 1, wherein the control unit performs control to irradiate the particle beam when the respiration waveform is an exhaled waveform after the irradiation is performed for each group. 4. Particle beam irradiation device. A step of generating a particle beam by a beam generator;
A step of a beam extraction control unit controlling the emission of the particle beam;
A beam scanning unit two-dimensionally scanning the particle beam;
A step of integrating signals according to the irradiation dose irradiated to the irradiation object by the dose monitor unit;
The center-of-gravity position calculation unit includes a plurality of first linear electrodes arranged in parallel in the first direction, and a plurality of second linear electrodes arranged in parallel in a second direction orthogonal to the first direction, Calculating a gravity center position of the particle beam from a first signal output from each first linear electrode and a second signal output from each second linear electrode;
A step of detecting a respiratory state of the irradiation object as a respiratory waveform by a respiratory waveform detector;
Information for correcting the displacement amount of the affected area of the irradiation target according to the respiratory waveform, and calculating the actual irradiation position from the displacement amount of the affected area, the respiratory synchronization correction processing unit;
A first control step of controlling the first control unit to irradiate a plurality of irradiation spots collectively for each group based on the displacement amount of the affected part, and
The first control step includes
An arbitrary number of irradiation spots are set as one spot group, and the region irradiated with the particle beam is divided into a plurality of spot groups,
Set an arbitrary spot group to irradiate the particle beam,
During irradiation of the particle beam, determine which irradiation spot in the spot group is irradiated with the particle beam based on the actual irradiation position,
Count the irradiation dose of each irradiation spot,
When one of the irradiation spots reaches a scheduled dose, the irradiation of the particle beam to the spot group is terminated and set to irradiate the particle beam to the next spot group,
When the irradiation to all the spot groups is completed, select the irradiation spot that has not reached the planned dose, and control to irradiate the particle beam when the waveform is breathing in the respiratory waveform, Particle beam irradiation , wherein when the selected irradiation spot reaches a planned dose, all the irradiation spots are controlled to reach the planned dose by selecting the irradiation spot that has not reached another planned dose Control method of the device. A step of generating a particle beam by a beam generator;
A step of a beam extraction control unit controlling the emission of the particle beam;
A beam scanning unit two-dimensionally scanning the particle beam;
A step of integrating signals according to the irradiation dose irradiated to the irradiation object by the dose monitor unit;
The center-of-gravity position calculation unit includes a plurality of first linear electrodes arranged in parallel in the first direction, and a plurality of second linear electrodes arranged in parallel in a second direction orthogonal to the first direction, Calculating a gravity center position of the particle beam from a first signal output from each first linear electrode and a second signal output from each second linear electrode;
A step of detecting a respiratory state of the irradiation object as a respiratory waveform by a respiratory waveform detector;
Information for correcting the displacement amount of the affected area of the irradiation target according to the respiratory waveform, and calculating the actual irradiation position from the displacement amount of the affected area, the respiratory synchronization correction processing unit;
A first control step of controlling the first control unit to irradiate a plurality of irradiation spots collectively for each group based on the displacement amount of the affected part, and
The first control step includes
An arbitrary number of irradiation spots are set as one spot group, and the region irradiated with the particle beam is divided into a plurality of spot groups,
Set an arbitrary spot group to irradiate the particle beam,
During irradiation of the particle beam, determine which irradiation spot in the spot group is irradiated with the particle beam based on the actual irradiation position,
Count the irradiation dose of each irradiation spot,
When one of the irradiation spots reaches a scheduled dose, the irradiation of the particle beam to the spot group is terminated and set to irradiate the particle beam to the next spot group,
When the irradiation of all the spot groups in the region is completed, the number of irradiation spots smaller than the setting so far is set as one spot group, and the spot group is reset in the region,
A particle beam irradiation method , wherein a spot group that does not include an irradiation spot that has reached a predetermined dose among the reset spot groups is set as a spot group that irradiates the particle beam. The respiratory synchronization correction processing unit changes a threshold for creating a respiratory gate signal for irradiating the particle beam when the waveform is exhaled in the respiratory waveform according to an irradiation situation, and an affected part corresponding to the respiratory waveform The method of controlling a particle beam irradiation apparatus according to claim 7 , further comprising a step of calculating an actual irradiation position from the amount of displacement. After the first control step, the second control unit further includes a second control step of controlling the particle beam to irradiate when the breathing waveform is in the breathing waveform. The particle beam control method according to claim 7 or 8 .

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